The present invention relates generally to a flat panel display device having a plurality of electron guns for providing electron beams to electron beam guides and particularly to such a display device in which the beam guides include means for modulating the electron beams.
U.S. Pat. No. 4,088,920 to W. W. Siekanowicz et al, entitled "Flat Display Device With Beam Guide", describes a beam guide for use in flat panel cathodoluminescent display devices. The display is composed of an evacuated envelope containing a plurality of internal support walls which divide the envelope into a plurality of parallel channels. Each channel contains a beam guide extending along one wall of the envelope. An electron gun structure emits electrons which are launched into the beam guides as electron beams. The beam guides include a pair of spaced parallel plates extending along and spaced from the back wall of the envelope. The plates have a plurality of aligned apertures therethrough with the apertures being arranged in columns extending longitudinally along the paths of the beams. Each longitudinal column of apertures constitutes a separate beam guide. The apertures also are arranged in rows transversely of the guides. One line of the visual display is generated by ejecting the electron beams out of the guide through the apertures in a single row.
Copending Application Ser. No. 921,267 filed July 3, 1978 by Charles H. Anderson et al, entitled "Guided Beam Display Device", discloses a flat panel display including multiple beam channels each of which encloses guide meshes extending along the length of the channels. Each of the channels includes modulation electrodes and cathode means which provide modulated electron beams to the guide meshes. Tabs are included on the guide meshes to determine the area where the electrons leave the cathode and enter into the beam guides. The guide meshes extend between the modulation electrodes so that the modulation electrodes partially overlap the beam guides. This overlap eliminates the deleterious effect of differences in the contour or misalignment of the edges of the modulation electrodes. The Anderson et al device therefore alleviates the problems of maintaining precise modulation electrode configuration, dimensions and spacing with respect to the cathode. However, the device does not permit the selection of the electron launching conditions independently of the conditions required for the operation of the cathode and modulation electrodes.